Peroxidase-like activity of MexFe3-xO4 Magnetic Nanoparticles with potential application in Magnetic Hyperthermia

A.C. MORENO MALDONADO; E. LIMA JR.; E.L. WINKLER; C.A. RAMOS; M. RAINIERI ANDERSEN; H.E. TROIANI; M.L. MOJICA PISCIOTTI; M.L. RODRIGUEZ; R.D. ZYSLER

S.C. de Bariloche

Simposio; XXIII Latin American Symposium on Solid State Physics (XXIII SLAFES); 2018

SLAFES

Magnetic nanoparticles (NPs) are widely used in medicine as contrast agents for MRI, oncology hyperthermia (MFH) therapy, and other applications. Due to their high magnetization,chemical stability and low toxicity, ferrite NPs,especially magnetite (Fe3O4), are applied clinically. In 2007, Gao et al. found that this material is capable of catalyzing the production of free radicals (FR) in the Fenton reaction because they possess peroxidase catalytic activity. FR are highly unstable, with paramagnetic behavior, that occur naturally in the body. In high concentrations they can induce oxidative stress, concluding with the death of the cells. For this reason, determining the peroxidaselike catalytic activity of magnetic NPs in dierent media is of vital importance.With this idea, the quantication of FR formation was performed using the Electronic Paramagnetic Resonance (EPR) spectroscopy technique with DMPO spin trap, which reacts with the short half-live FR producing a more stable radical with a longer half-life that can be measured. Three nanoparticle systems were used: Fe3O4, MnFe2O4 and NiFe2O4 prepared by the thermal decomposition of iron acetylacetonate at high temperature in the presence of surfactants. The NPs were characterized morphologically by TEM microscopy, chemically by EDS, XPS and FTIR, and magnetically by magnetization measurements as function of applied eld and temperature. The EPR spectra were taken at 293 K, 313 K and 318 K. The areas of the lines were adjusted, taking into account the hyperne interactions of each radical bound to the DMPO. The spectra reveal hydroxyl (OH) and superoxide (OOH) radicals from the H2O2 decomposition together with the methyl radical (CH3) from the DMSO in which the DMPO was dissolved. To ensure quantication, all spectra were compared with a standard sample of Mn2+ : MgO.